May 5, 2015 -- A screening method that uses blood tests can detect twice as many cases of ovarian cancer as older testing methods, and that may lead to women getting diagnosed sooner, researchers say.
The new approach looks at how levels of a protein linked to the disease change over time in a woman’s blood, they say.
The method uses a formula to interpret the changing levels of the “CA125” protein, says study researcher Usha Menon, MD, professor of gynecologic oncology at University College London.
The formula looks at a few things: a woman’s age, the overall rate of ovarian cancer at that age, and the woman’s CA125 profile over time, Menon says.
The formula also takes into account profiles of many other women, some of whom ended up getting ovarian cancer. A woman is then given a risk level based on all these things. Doctors can use that risk level to decide whether she needs more tests or treatment.
This year in the U.S., more than 21,000 women will get a diagnosis of ovarian cancer, according to the American Cancer Society. More than 14,000 women are expected to die of it. While ovarian cancer accounts for only 3% of all cancers in women, more die from it than from any other cancer of the female reproductive system.
Only about 20% of ovarian cancers are found early, because many women don’t have symptoms. When symptoms do show up, they can be vague, such as bloating and belly pain.
While the results of the new study show a lot of promise, “we are not there yet,” Menon says. "We know we have picked up the cancer earlier, we have been able to treat them earlier. But whether this translates to saving lives, we don't know yet.”
Benefits of the Method
The study, published in the Journal of Clinical Oncology, is one part of a large ovarian cancer screening trial that started in the mid-'90s and continued for 14 years. Menon and her colleagues evaluated more than 46,000 women who had their blood tested once a year for CA125 levels.
In the past, using CA125 to predict the risk of ovarian cancer was questioned, because it often led to test results that incorrectly pointed to cancer.
In this study, though, researchers found cancer in women that would have been missed using the old methods.
The new method picked up 86% of the women with cancer. The conventional tests picked up only 41% to 66% , depending on the test, Menon says.
In all, 640 women had surgery for suspected ovarian cancer based on their risk level, and 133 were found to have invasive cancer. Another 22 were diagnosed with ovarian cancer within a year of their last yearly screen, she says.
Second Opinion on the New Approach
"It's definitely exciting, it's promising,'' says Debbie Saslow, PhD, director of cancer control intervention for the American Cancer Society. Experts have been waiting for the results of this study for years, she says.
But, she says, information on whether it saves lives is crucial. Complicating the issue, she says, is that experts aren't certain about how all ovarian cancers will develop over time. Some get worse than others, she says.
In the study, just 133 of the 640 women who had surgery actually ended up having ovarian cancer, she points out.
If the research shows that the new method not only finds more cancers, but saves lives by doing so, Menon says the test could be used routinely in all women from age 50 on, when risk for the cancer rises.
Researchers should know more about that by the end of the year, she says, when a final breakdown of the results from this study is expected.
Experts would need to look at all the data, including the information on the method's ability to save lives from ovarian cancer, and make recommendations, Saslow says.
Her prediction, if research continues to bear out? "It's highly likely to be used clinically for high-risk women, probably for women with symptoms, and there's a big question mark for women who are not at high risk and don't have symptoms."